The present invention relates to the field of semiconductor technology. Specifically, embodiments of the invention are directed to semiconductor substrate structures, devices, and manufacturing methods.
Currently, gallium arsenide (GaAs) is often used in advanced CMOS devices and bipolar devices, because compared to pure silicon (Si), GaAs can provide a higher hole mobility. Similar to the GaAs, silicon germanium (SiGe) is often used for advanced CMOS devices and bipolar devices, because SiGe can also provide higher mobility of holes. In addition, RF (Radio Frequency) devices often require high insulating properties. Therefore, SOI (silicon on insulator) wafers are being using widely in RF applications.